1. Field of the Invention
The present invention relates to apparatus for nullifying the effects of the heaving movements of a platform in the measurement of the amount of pipe being run into a well.
2. Description of the Prior Art
In the past, various mechanisms have been developed which measured the amount of pipe being lowered into a well, as exemplified by U.S. Pat. No. 3,747,218. These mechanisms were developed for land-based derrick platforms and are not satisfactory for use on offshore floating drilling platforms since such platforms heave up and down in response to wave action and thereby do not provide a stationary reference point for the measurement of the movement of pipe into a well. Hence, such mechanisms provide false readings of the movement of pipe into off-shore wells.